Proper regulation of gene expression is critical for normal cellular function and is frequently altered during viral infection and in certain diseases such as cancer. This proposal examines some of the mechanisms of gene expression by RNA polymerase II (RNAP II), which unlike RNAP III can regulate elongation, capping, splicing and polyadenylation of its transcripts. The carboxy terminal domain (CTD) of the largest subunit of RNAP II is necessary for all of these processes. The experiments in this proposal will test whether the CTD in the context of RNAP III is sufficient for these processes. To address this question, the CTD of RNAP II will be cloned onto the largest subunit of RNAP III. The RNAP III plus CTD enzyme will be evaluated for its responsiveness to positive and negative elongation factors and for its ability to direct the capping, splicing and polyadenylation of RNA whose synthesis is directed by a RNAP III promoter.